This allows you to connect up to 4 solar panels with no soldering.
It comes with the Solar Panel Connector board and a 20cm female to female JST-PH 2 cable for connecting the board to SunAirPlus, SunAir or other Solar Power Charger Boards. The solar panel plugs are also JST-PH 2 connectors.
The Solar Panel Connector Board has four diodes that protect the up to four solar panels and keeps the current flow heading for the battery even if one of the solar panels dies or is in the shade while the others are still working.
The attached diodes are a Schottky 40 Volt 3A diode. Note, this board is limited to connecting 6V Solar Cells, even if the diode is rated at 40V. We choose the diode for it's low forward diode drop (Vf = 0.45V) and the current rating.
While we designed this board for use with OurWeather, it will work equally well with any of our other solar products.
While we designed this board for use with OurWeather, it will work equally well with any of our other solar products:
It seems that 4 power diode are or-ed into single node which makes me worry about its efficiency. When a single solar panel is turned on, others are turned off because the diodes other than biased with the highest voltage are reverse biased.
No, it all works well. You can make the argument that if you connect all the solar panels under no-load that some of the diodes may be not forward biased.
However, when you are actually using the solar cells, the output pulled down much lower than 6V until the battery is fully charged, and then when the battery is fully charged, you don't care.
To show you how this works, here is some data. The first measurement is with one solar panel turned up and one solar panel turned down. We are measuring this with our SunAirPlus solar power charger and data connector.
Solar Cell Bus Voltage 2: 4.62 V
Solar Cell Load Voltage 2: 4.62 V
Solar Cell Current 2: 17.20 mA
Then we turn both solar panels upright and we get much more current.
Solar Cell Bus Voltage 2: 4.66 V
Solar Cell Load Voltage 2: 4.65 V
Solar Cell Current 2: 37.20 mA
The solar panels are identical, but they don't quite fit under the test light panel, so it more than doubles with the second one connected. The same would be true with four solar panels. Hope that explanation helps!